Re: [PATCH v2 19/19] tests/tcg: take into account expected clashes pauth-4

[Richard Henderson]

On 2/13/20 2:51 PM, Alex Bennée wrote:
> Pointer authentication isn't perfect so measure the percentage of
> failed checks. As we want to vary the pointer that is authenticated we
> recurse down the stack.
> 

You're no longer recursing.

> Signed-off-by: Alex Bennée <address@hidden>
> ---
>  tests/tcg/aarch64/pauth-4.c | 54 +++++++++++++++++++++++++------------
>  1 file changed, 37 insertions(+), 17 deletions(-)
> 
> diff --git a/tests/tcg/aarch64/pauth-4.c b/tests/tcg/aarch64/pauth-4.c
> index 1040e92aec3..24a639e36ca 100644
> --- a/tests/tcg/aarch64/pauth-4.c
> +++ b/tests/tcg/aarch64/pauth-4.c
> @@ -1,25 +1,45 @@
>  #include <stdint.h>
>  #include <assert.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +#define TESTS 1000
>  
>  int main()
>  {
> -  uintptr_t x, y;
> +    int i, count = 0;
> +    float perc;
> +    void *base = malloc(TESTS);
> +
> +    for (i = 0; i < TESTS; i++) {
> +        uintptr_t in, x, y;
> +
> +        in = i + (uintptr_t) base;

There's no reason all of these couldn't be char* or void* instead of casting to
uintptr_t.  Nothing else would have to change.

> +
> +        asm("mov %0, %[in]\n\t"
> +            "pacia %0, sp\n\t"        /* sigill if pauth not supported */
> +            "eor %0, %0, #4\n\t"      /* corrupt single bit */
> +            "mov %1, %0\n\t"
> +            "autia %1, sp\n\t"        /* validate corrupted pointer */
> +            "xpaci %0\n\t"            /* strip pac from corrupted pointer */
> +            : /* out */ "=r"(x), "=r"(y)
> +            : /* in */ [in] "r" (in)

It's weird to have some arguments named and some not.  Why not just use %2,
since this is simple enough?

Otherwise,
Reviewed-by: Richard Henderson <address@hidden>

r~